You could come out with a nifty line of stylus "pens" in fun colors with your logo and then with the purchase of the stylus could come a "stylus-holder-only" feature. Something ingenious that everyone will want to have but will have to get the pen first! Just a thought bc I went ahead and purchased a stylus for using the app anyway since I figured my finger would get annoying. Since many people might be doing that same thing for Squid specifically why not tap into that market (& create a unique "squilus," a squid-stylus, pronounced squ-eye-lus".) But in all seriousness I think it's a market that you definitely need to get into! Shorter ones for kids, 5-6" for adults, double ended, many many options!
Thanks for this awesome app!!